This invention relates to systems for regulating the high voltage (EHT) applied to the anode of a cathode ray tube. The invention is particularly applicable to X-Y monitors and data/graphics video projectors, for example, where the frequencies of the deflection signals are not constant and, hence, are not used to derive the EHT. However, the invention also may be used in raster-scan systems, e.g., conventional television receivers, as long as the conventional horizontal deflection circuitry thereof, which operates at a constant frequency, is not used for deriving the EHT.